The separation of radish peroxidase from a fresh Raphanus sativus L extract was carried out using precipitation with two commercially available negatively charged synthetic polyelectrolytes: Eudragit (R) L 100 and Eudragit (R) S 100. The enzyme was precipitated by polyelectrolyte addition at pH 4.00. The non-soluble complex formed was separated by simple centrifugation and re-dissolved by a pH change. The recovery of radish peroxidase biological activity was 50% of the initial activity in the homogenate for EuL and 45% for EuS, with 1.5-fold increase in its specific activity. The total Eudragit (R) concentration to precipitate the enzyme was very low: about 2 x 10(-3)% w/v. The volume of the final product decreased to 10% of the feedstock, concentrating the sample up to 10 times. (C) 2013 Elsevier B.V. All rights reserved.